This invention relates generally to hydraulic nonmechanical pumping devices for transferring material, and specifically, to jet pumps for moving solid, semi-solid and/or liquid materials, as well as related methods.
Our previous invention described in U.S. Pat. No. 6,322,327 B1 provides a jet pump with significantly increased vacuum efficiency, resulting in the ability to move greater amounts of solid or slurry materials without a proportionate increase in energy consumption. While that pump configuration has made a significant contribution in the field of pump efficiency and capabilities, the material being vacuumed or suctioned in that pump configuration typically is mixed with the motive fluid of the jet pump. This can present difficulties where the material being pumped might become volatile when placed in contact with the motive fluid or when the material being pumped is preferably be kept separate from the motive fluid for other reasons. Also, our previous developments still required significant volumes of motive fluid in many commercial scale pumping operations.
Thus, a need has continued to exist for a jet pump which does not require a large volume of motive fluid in commercial operations, and which allows a user to keep pumped material separate from the motive fluid of the jet pump.
The present invention meets these and other needs by providing, among other things, apparatus comprising:
(a) a jet pump in fluid communication with a passageway for a material to be suctioned, the jet pump being sized and configured to create a vacuum in the passageway when the jet pump is in use;
(b) a motive fluid pump sized and configured to supply a motive fluid to the jet pump; and
(c) a motive fluid reservoir downstream from the jet pump, the motive fluid reservoir being in fluid communication with the jet pump and the motive fluid pump so that during use the motive fluid pump recirculates at least a portion of the motive fluid from the motive fluid reservoir to the jet pump;
wherein the jet pump is comprised of a nozzle assembly which is sized and configured to (A) receive the motive fluid and a gas, and (B) eject the motive fluid as a liquid flow while feeding the gas into proximity with the periphery of the liquid flow. Preferably, the jet pump in apparatus of this invention is further comprised of a housing defining a suction chamber into which the nozzle assembly may eject the liquid flow, the housing further defining a suction inlet and a suction outlet; and an outlet pipe extending from the suction outlet away from the suction chamber, the outlet pipe being in fluid communication with the suction chamber and being disposed to receive the liquid flow; the outlet pipe defining at least a first inner diameter along a portion of its length and a second inner diameter along another portion of its length, the second inner diameter being less than the first inner diameter. It is particularly preferred in certain applications that the nozzle assembly extend into the suction chamber towards the suction outlet and into the imaginary line of flow of the suction pipe.
In another embodiment of the invention, the apparatus further comprises a material collection reservoir which is sized and configured to permit the formation of a vacuum therein. In this embodiment, the collection reservoir is intermediate to, and in fluid communication with, the passageway for the material to be suctioned and the jet pump. This collection reservoir allows material which is suctioned to be collected without mixing with or otherwise contacting the motive fluid of the jet pump.
Yet another embodiment of this invention provides a method of moving material from one location to another. The method comprises:
a. injecting a pressurized fluid into a nozzle assembly to produce a flow of pressurized fluid,
b. providing a gas to the nozzle assembly to surround the flow of pressurized fluid with the gas,
c. directing the flow of pressurized fluid surrounded by the gas into a suction chamber which defines both an inlet in fluid communication with a collection reservoir and an outlet in fluid communication with an outlet pipe, the outlet pipe defining a venturi-like inner surface, and directing the flow of pressurized fluid surrounded by the gas into the outlet pipe to produce a vacuum in the collection reservoir,
d. suctioning the material to be moved into the collection reservoir using the vacuum produced in step (c.), and
e. recirculating at least a portion of the pressurized fluid directed into the outlet pipe back into the nozzle assembly.
In a preferred embodiment of this invention, the material to be moved is liquid material from a slurry comprised of a mixture of solid material and liquid material. The suctioning of step (d.) is carried out after placing the collection reservoir in fluid communication with a slurry container and equipped with a filter so that, when a vacuum is created in the collection reservoir, a vacuum is created in the slurry container and liquid material from slurry within the slurry container is suctioned through the filter and into the collection reservoir while solid material remains in the slurry container. This preferred embodiment thus enables the removal of liquid from the slurry without mixing or otherwise bringing together the separated liquid material with the motive fluid of the jet pump. In another preferred embodiment of this invention, the method further comprises the step of controlling the flow rate of the gas into the nozzle assembly to thereby control the level of vacuum produced in the suction chamber.
These and other embodiments, advantages, and features of this invention will be apparent from the following description, accompanying drawings and appended claims.